Seborrhoeic dermatitis is a chronic inflammatory skin disease which occurred in the scalp and face in which sebaceous glands are highly abundant, particularly, eyebrows, a nose, lips, ears, armpits, chests, the groin, and the like. In this case, a condition whose symptoms appear slightly on the scalp is referred to as ‘dandruff.’
Dandruff means that dead or scaly cells of the scalp formed by active metabolism of the human body are desquamated in the form of horny mass, which is formed when the cells are caked with secretions from the sebaceous glands of the scalp.
In a histological aspect of dandruff, new cells are formed in the stratum basale of the scalp epidermis, and pushed up. When the cells pushed up to the uppermost layer of the stratum corneum, the cells are desquamated. In this case, the old cells barked off become dandruff. Approximately one month is generally required until the cells are formed and desquamated, which is referred to a turn-over of the cells. An amount of dandruff increases as such a turn-over cycle is shortened, and ichtyosis is caused by secretion and accumulation of sebum due to dysfunction in secretion of lipids from sebaceous glands, living habits or stress, abnormalities in environments such as ambient temperature or moisture, or abnormalities in hormones, depending on the individual difference, sex, age, etc. As a result, a turn-over cycle of epidermal cells is shortened by stimulants such as free fatty acids generated when skin fungal flora or fungi of the skin fungal flora decompose triglycerides in lipids, the stratum corneum gets thick and hyperkeratosis appears since the cell divisions in the stratum corneum more actively occur than those of normal persons, scales are observed with the naked eye, the infiltration of inflammatory cells occurs, and inflammatory findings are partially observed.
The term “ichtyosis” refers to a condition in which an amount of such dandruff increases to a level at which the dandruff is observed with the naked eye. In numerous cases, the ichtyosis easily recurs, and is accompanied by pruritus. When ichtyosis develops, the scalp is excessively rubbed due to dandruff or itching, resulting in damaged scalp. In some cases, the ichtyosis may cause inflammation in the scalp, or often becomes a cause of hair loss. Therefore, dandruff is a kind of seborrhoeic dermatitis which develops in the scalp, and is known to be a symptom developing when secretions of sebaceous glands, secretions of sweat glands, keratinizing materials of the outer skin layer, and the like are generated and accumulated, and infected with microorganisms. Generally, dandruff is characterized in that it often occurs in the face, head, armpit, pubes, and the like, in which the sebaceous glands are functioning actively, and develops immediately after the birth or during puberty.
In recent studies, it is known that skin fungal flora (i.e., dandruff-causing organisms) is deeply associated with the occurrence of dandruff, and yeast has been currently identified as causing dandruff. Among these, Eumycetes (yeasts) referred to as Pityrosporum ovale or Malassezia furfur are found to be associated with the occurrence of dandruff, and thus interest in the Eumycetes is currently increasing.
Therefore, much research has been conducted to improve ichtyosis by effectively removing dandruff-causing organisms. Particularly, zinc pyrithione and piroctone olamine have been proven to have an inhibitory effect on dandruff and pruritus, and thus have been widely used as antidandruff agents for hair care cosmetics. Zinc pyrithione may be problematic at a concentration of 1% or more since it is an irritant to the skin, and has a poor effect at a concentration of 0.01% or less. Preferably, zinc pyrithione is mixed at a concentration of 0.5%, and used. Zinc pyrithione has an advantage in that it is effective for treatment and improvement of ichtyosis since it has a good effect of suppressing hyperkeratosis of the scalp and a good antifungal effect. However, zinc pyrithione has problems in that it is difficult to uniformly disperse in a composition since it is insoluble in water and has a high specific gravity, and it is restricted to apply a high concentration of zinc pyrithione to hair care cosmetics since it particularly has problems about contact dermatitis to the skin (Nielsen, N. H., Allergic contact dermatitis caused by zinc pyrithione associated with pustular psoriasis. Am J Contact Dermat. 8, 170, 1997), environmental toxicity, and the like.
Meanwhile, as a water-soluble therapeutic agent for treating dandruff which compensates for the shortcomings of zinc pyrithione, piroctone olamine should be used at a concentration of 0.5 to 2.0% to exhibit a sufficient effect. In this case, such a component also tends to be regulated on its usage due to safety issues to the human body (Cosmetics and Toiletries, 102, 6, December, 1987). In addition, climbazole, sulfur, salicylic acid, tar, and the like have been used as antidandruff agents since they have an antibacterial effect on Pityrosporum ovale that is a microorganism present in the scalp.
From the foregoing, a combination therapy capable of compensating for an effect of the antidandruff agent while reducing a concentration of the antidandruff agent is required. In particular, although such a synthetic material has antibacterial activities, since consumers may have negative thoughts about the synthetic material in that it is not safe due to side effects in the skin, a natural substance-derived composition for preventing dandruff is required.
Meanwhile, although Pityrosporum ovale is often found in the scalps of ichtyosis patients, only suppressing this strain does not essentially mean improving ichtyosis. Accordingly, an issue where there is another cause of ichtyosis has been raised.
Filobasidium sp. is a fungus that belongs to the fungal class of Tremellomycetes. Among these, a family of Filobasidiaceae is divided into four species. This fungus has a characteristic of having no macroscopic basidiocarp observed with the naked eye unlike other Tremelloid species.
The fungus is the skin flora, and methods using the fungus to produce alcohol are disclosed in the prior art, but the fungus is still not identified as causing dandruff.
The present inventors have conducted research on the cause of dandruff, and found that there is a significant increase in the number of the fungus Filobasidium sp. in the scalps of ichtyosis patients, and that the fungus is identified as mainly causing dandruff. Therefore, they have contemplated that it is possible to prevent or treat ichtyosis by effectively removing these dandruff-causing organisms.
Accordingly, the present inventors have searched for materials which are environmentally and ecologically friendly, and having an effect of preventing and treating dandruff without causing safety issues to the human body, and confirmed that an extract derived from a fruit of Gardenia jasminoides Ellis, a fruit of Poncirus trifoliata, Saururus chinensis, Benincasa hispida, or a fruit of Capsella bursa-pastoris has an anti-Filobasidium effect. Therefore, the present invention has been completed based on these facts.